An analysis of preprogrammed reactions in global muscles of Lumbo Pelvic segment in subjects with and without low back pain experimental electromyographic study

Abstract

This work primarily explores the reflex level neuromuscular activation i.e., Preprogrammed Reaction (PPR) and its contribution to perturbation induced trunk global muscle responses of Chronic Low Back Pain (CLBP) population compared to healthy individuals. This experimental study clearly revealed that patients with CLBP had lower or absence of PPR amplitude with higher peak voluntary responses compared to asymptomatic population, indicating dysfunction in preparing voluntary responses to counter perturbation. Further we examined the influence of kinesiophobia on perturbation induced electromyographic global trunk muscle voluntary responses with PPRs in persons with chronic low back pain. Our study confirms that kinesiophobia in CLBP patients differentially influence the trunk muscle activation during sudden postural demands and found substantial evidence that fear of movement is associated with direction specific movement dysfunction rather than whole task. Deficit in neuromuscular activation patterns and strategies is associated with impaired postural control of lumbar spine in CLBP patients. Hence we examined postural stability characteristics during commonly used functional tasks between CLBP and normal healthy population. The kinetic variables of postural control in CLBP population was examined through pragmatic clinical control trial to find out the variables sensitive to functional core stability exercises in CLBP. As the functional task difficulty increases CLBP patients exhibited significantly different postural stability characteristics compared to healthy participants. The results of clinical trial on CLBP population found significant improvements in kinetic as well as clinical outcomes, i.e., efficient distribution of ground reaction forces, use of optimized postural adjustments in the direction of perturbation, 20% absolute risk reduction of flare-up during intervention and 40% absolute risk reduction for resolution of back pain after core instability exercises in specific subgroup of CLBP patients.